Radiotelephones are widely used for wireless voice and/or data communications. As used herein, the term "radiotelephone" includes analog and digital radiotelephones, multiple mode radiotelephones, high function Personal Communications Systems (PCS) devices that may include large displays, scanners, full size keyboards and the like, wireless Personal Digital Assistants (PDA) and other devices, such as personal computers that are equipped with wireless modems and other wireless electronic devices.
It may be increasingly difficult to efficiently couple an antenna to a radiotelephone transceiver. In particular, in many radiotelephone applications, the radiotelephone is located within an enclosure such as a vehicle or a building. However, it may be desirable to include the antenna outside the enclosure in order to provide adequate link margin. For example, in radiotelephone communications involving radio links between a mobile vehicle and a communication satellite, it is generally desirable for the antenna to be outside the vehicle. It is also generally desirable to have a radio frequency receiver unit near the antenna in order to allow an improved receiver antenna gain to receiver system temperature ratio. Moreover, as a practical matter, it also may be desirable to include a transmitter power amplifier near the antenna, to overcome transmission loss between the antenna and the transceiver.
It is known to provide an external electronic package or module adjacent an antenna outside a vehicle window, to thereby improve the performance of a radiotelephone within a vehicle. Unfortunately, external electronic packages may be subject to environmental hazards and damage by vandals. Other hazard potentials include automatic car washing facilities that can damage external electronic packages.
Moreover, it may be difficult to couple an electronic package outside the window to a radiotelephone inside the vehicle. It may be unacceptable to cut holes in the widow or other parts of the vehicle body. The running of coaxial cables through doorjambs may not be acceptable. Accordingly, although outdoor antenna units that combine an antenna and an electronic package have been used in the trucking industry or in marine applications (such as the INMARSAT-C system), it may be generally undesirable for terrestrial cellular and satellite radiotelephone communications systems such as the Iridium, Globalstar and ACeS systems.
It is also known to allow a radiotelephone antenna to be used within an enclosure such as a building or a vehicle. While this solution may be acceptable for many cellular radiotelephone communications, it may not be desirable for satellite radiotelephone communications which may have low link margins and which preferably operate in a direct line of sight path between the radiotelephone and the communications satellite.